I think people "get" when it is just sharing. Like, "Sometimes I worry about whether I'm being a good mom, but Susie's teacher called today to say that she did this good thing at school....." Or if you are excited about going on a trip with your family. I don't consider that bragging at all.
I have a friend I really love, but she has a major issue with this. She brags A LOT. With her I know when its bragging because its about how much $$$ her husband is making, like, "Sam is working sooo many hours, but since he became VP and is making $250K, I guess I can't complain." Or it's about how they are looking at a house that is a zillion square feet or how they ALWAYS stay at the Polynesian hotel at Disney because others are sooo unacceptable.
THAT'S bragging.
When she's talking about her kids or great things she did herself, there's just a change I can't explain. Personally I think she "needs" the bragging to feel good about her situation.
Also, I don't think that bragging is necessary a bad thing, it just needs to be done in moderation. Hope that helps.